Java--用简单工厂来改进抽象工厂（反射）

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接上一篇抽象工厂，改进方案去除IFactory、SqlServerFactory和AccessFactory三个工厂类取而代之的是DataAccess类，用一个简单工厂模式来实现。

1、DataAccess类

public class DataAccess {private static final String db = "SqlServer";//private static final String db = "Access";public static IUser createUser(){IUser result = null;switch (db) {case "SqlServer":result = new SqlServerUser();break;case "Access":result = new AccessUser();break;default:break;}return result;}public static IDepartment createDepartment(){IDepartment result = null;switch (db) {case "SqlServer":result = new SqlServerDepartment();break;case "Access":result = new AccessDepartment();break;default:break;}return result;}}

2、测试

public class Test {public static void main(String[] args) {User user = new User();Department department = new Department();IUser iu = DataAccess.createUser();iu.insert(user);iu.getUser(1);IDepartment id = DataAccess.createDepartment();id.insert(department);id.getDepartment(1);}}

3、使用反射机制再优化

public class DataAccess {// 包名private static final String AccemblyName = "com.test.factory.abstractmethod";// 可以替换成Accessprivate static final String db = "Access";public static IUser createUser(){IUser result = null;String className = AccemblyName + "." + db +"User";Class<?> user = null;try {user = Class.forName(className);result = (IUser)user.newInstance();} catch (ClassNotFoundException e) {e.printStackTrace();} catch (InstantiationException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}return result;}public static IDepartment createDepartment(){IDepartment result = null;String className = AccemblyName + "." + db +"Department";Class<?> department = null;try {department = Class.forName(className);result = (IDepartment)department.newInstance();} catch (ClassNotFoundException e) {e.printStackTrace();} catch (InstantiationException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}return result;}}

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